Fluid device



Nov. 25, 1969 RANDA ET AL 3,479,963

FLUID DEVICE Filed Oct. 18, 1967 3 Sheets-Sheet l 1/QZZ for NOV. 25,1969 5, RANDA ET AL FLUID DEVICE 3 Sheets-Sheet 2 Filed Oct. 18, 1967Nov. 25, 1969 RANDA ET AL 3,479,963

FLUID DEVICE Filed Oct. 18, 1967 3 SheetsSheet 3 United States PatentUS. Cl. 103162 14 Claims ABSTRACT OF THE DISCLOSURE A fluid pressuredevice having a rotating cylinder barrel, a port block and a valve platebetween said cylinder barrel and the port block. The device includingintake and discharge ports in the valve plate including a seal or pistonassembly surrounding said ports and responsive to fluid pressure toprovide a seal between the valve plate.

and the port block and pressure responsive surfaces providing acontrolled force to maintain sealing between the valve plate and therotating cylinder barrel.

SUMMARY OF THE INVENTION An improved construction for fluid pumps ormotors comprising a valve plate mounted between the cylinder barrel ofthe pump or motor and a port block, the valve plate being mounted onsaid port block in a manner allowing slight movement of the valve platewith respect to the port block. The valve plate includes intake anddischarge ports surrounded by arcuate shaped counterbores in which aremounted piston assemblies having a piston member movable in saidcounterbore in the valve plate and in contact with said port block.Fluid pressure urges said piston member into engagement with said port'block whereby a fluid seal is maintained regardless of misalignment ofthe parts of the pump or motor. Fluid pressure responsive areas definedby the counterbores in the valve plate and are provided on the valveplate in the vicinity of the piston assemblies which provide a forcethat overcomes the separating force between the valve plate and thecylinder barrel of the pump and provides a precise sealing force betweenthe valve plate and the cylinder barrel.

DESCRIPTION OF THE DRAWINGS The invention consists of the novelconstructions, arrangements and devices to be hereinafter described andclaimed as will appear from the following description of a preferredembodiment of the invention illustrated with reference to theaccompanying drawings wherein:

FIGURE 1 is a cross-sectional view through a fluid pump or motorstructure embodying the present invention;

FIGURE 2 is an enlarged sectional view of a portion of FIGURE 1;

FIGURE 3 is a view taken along the line 33 of FIGURE 1;

FIGURE 4 is a view taken along the line 44 of FIGURE 1;

FIGURE 5 is a view taken along the line 55 of FIGURE 1;

FIGURE 6 is a view taken along the line 66 of FIGURE 1;

FIGURE 7 is a cross-sectional view of a modified form of the invention;and

FIGURE 8 is a view taken along the line 8-8 of FIGURE 7.

ice

Referring to FIGURE 1, a fluid pump or motor mechanism 10 isillustrated. If the mechanism of FIGURE 1 is to operate as a pump, shaft11 serves as a drive shaft to rotate a cylinder barrel 12 of the pump10. If the mechanism is used as a fluid motor, shaft 11 would be thedriven or output shaft of the driving motor 10.

Provided in the cylinder barrel 12 are a plurality of cylinders 13 eachreceiving a fluid piston 14. Cylinder liners or bushings 14a areprovided in which pistons 14 reciprocate. The pump mechanism iscontained within a housing 15; a thrust bearing 16 is mounted within thehousing receiving the end of the driving shaft 11.

A fixed swash plate 20 is provided for the pump. However, it will beobvious that the present invention is primarily designed to work withvariable displacement pumps having a variable angle swash plate althoughthe fixed swash plate is illustrated to simplify the description. Aretaining clamp 21 is mounted on the swash plate 20, for example, bybolts 22. The retaining clamp 21 engages a plate 24 which in turnengages slippers 25 provided on the ball shaped end of the pistons 14.Thus as the barrel 12 of the pump is rotated by the shaft 11 the swashplate 20 causes the pistons 14 to reciprocate within the cylinders 13 toalternatively take in and displace fluid from the cylinders.

A port block is provided on one end of the housing 15 to enclose thehousing and may be secured to the housing in any known manner. The portblock 30 has a central bore 31 through which the shaft 11 passes.Mounted between the cylinder barrel 12 and the port block 30 is a barrelplate 35 which is drivingly connected to shaft 11 to rotate withcylinder barrel 12 and a nonrotating valve plate 36. However, thecylinder barrel 12 may be manufactured with the barrel plate 35 integralwith the cylinder barrel 12.

The valve plate 36 as can be seen by reference to FIG- URE 3 includes abore 37 and a slot 38 on opposite sides thereof. Pins 40 mounted in theport block 30 are received in the bore 37 and the slot 38 of the valveplate 36. The pins 40 locate the valve plate within the assembly butallow slight relative movement of the valve plate 36 with respect toport block 30 to compensate for misalignment.

A pair of counter bores 41 and 42 are formed in the valve plate 36 whichare intercepted by small bores 43. Received Within the counter bores 41are pressure buttons 48 and resilient means 49 comprising O-rings whichin the FIGURE 1 construction provide a pressure balancing function inthe pump to be described later.

Also provided in the vlave plate 36 (see FIGURE 3) is a pair of arcuatepassages or ports and 56 which constitute the fluid inlet and outlet orpressure passages for the pump. Mating passages, not illustrated, areformed in the port block 30 and are suitably connected to the outputline from the pump and the inlet line from the sump.

A piston or sealing assembly is provided for each of the arcuate ports55 and 56 although a piston assembly is necessary only for the highpressure port (the outlet port if the device is acting as a pump or theinlet port if the device is acting as a motor). The piston assembly 60,as can be seen in FIGURE 2, surrounds the ports and is mounted on theperiphery of the ports 55 and 56 within the valve plate 36 in a steppedarea 58 having a pressure responsive surface 59.

The piston assembly 60 for each of the arcuate ports comprises a pistonmember 61, a pressure or resilient member 62 and a retainer 63 eachhaving an arcuate kidney shape similar to ports 55 and 56. The pistonmember 61 engages the port a material having sufficient resistance todeformation to maintain a precise area engaging the port block asdefined by the size of the counterbore in which the piston is mountedwhereby the piston will maintain a fluid seal between the valve plateand the port block and will not be deformed to exceed the area limitdefined by the bore and extrude into the area between valve plate 36 andport block 30. The pressure member 62 is comprised of rubber like orother elastic material which may deform when subjected to fluid pressureand establish a fluid seal between the piston 61 and bore 58. However,pressure member 62 is primarily a sealing member and acts along withpiston member 61 as an annular piston in response to fluid pressure andmay or may not deform depending upon the pressure involved and thecomposition of the material used. Other shapes of pressure members suchas member 62 may be used as, for example, a common ring shape.

The piston assembly 60 is constructed such that when the pump isassembled deformation of the pressure member 62 takes place therebyproviding a pressure loading characteristic within the pump so that acertain predetermined sealing force between piston member 61 and theport block exists.

Referring to FIGURES 4 and 5, barrel plate 35 comprises a plate having aseries of kidney shaped ports 70 with each port 70 connecting with oneof the cylinders 13. The ports 70 are arcuately shaped as can be seen inFIG- URE 4 and are generally of a smaller radial dimension than thecylinders 13 as can be seen in FIGURE 1, thus providing an area 76 onthe barrel plate 35 which in effect partially closes the end of thecylinders 13. However, the ports 70 may be widened to the same radialdimension as cylinder 13, if desired, providing thrust bearing 16 hasthe capacity for the increased pressure loading which would be required.

The barrel plate 35 on the side adjacent the valve plate 36 has relievedareas 72 and 73 which form raised areas 74 surrounding the ports 70 anda series of raised areas 75 around the outer periphery of the barrelplate. By controlling the radial width of the arcuate ports in thebarrel plate and in the valve plate, and the radial width of the sealingland of the valve plate, the fluid caused separating force generatedbetween the valve plate and the barrel plate is controlled to be lessthan the total sealing force of the fluid pressure behind the severalpistons so that a precise sealing force is maintained between the valveplate and the barrel plate. On the side of the barrel plate 35 adjacentthe cylinder barrel 12 raised areas 76 are provided surrounding theports 70 and a series of radial raised ribs 71 are provided extending tothe outer periphery of the barrel plate 35. As in the case of the areason the other side of the barrel plate by restricting the raised areas 76provides a higher force per square inch ratio to insure a good fluidseal around the ports 70. The ribs 71 are formed to support the barrelplate 35 and prevent warpage of the plate under high fluid pressures.

It can be seen that by controlling the area of the raised sections oneither side of the barrel plate 35 the sealing force on any of thesealing areas of the barrel plate may be selectively controlled.Further, the barrel plate of the subject device has kidney shaped ports70 which extend through the barrel plate 35. An optional construction isto have the arcuate port such as port 70 on the side of the barrel plateadjacent the cylinder barrel dished out to generally conform to thecircular shape of the cylinders in the cylinder barrel. However, it hasbeen found that by making the through ports 70 as illustrated in FIGURE5, pump efficiency is maintained while at the same time the manufactureof the barrel plate is greatly simplified since the machining requiredto form the circular dished out shape around the port 70 is eliminated.

Referring to FIGURE 6 a retainer 82 is provided which is splined on thedrive shaft 11. The retainer 82 engages a shoulder on the shaft 11 andthe cylinder barrel is assembled to the shaft 11 and retained inposition by the retainer 82.. Arcuate areas 83 are provided on theretainer 82 to provide clearance for the pistons 14. The retainer 82 isshaped with arcuate areas 83 such that the retainer 82 engages the endsof bushings 14a and serves to positively secure bushings 14a in thecylinders 13.

During operation of the fluid pump 10 as the cylinder barrel 12 isrotated, pistons 14 will move in one direction of increasingdisplacement as they pass the arcuate port 55 for example, so as to drawfluid into the cylinder through port 55 and will move in the directionof decreasing displacement as they pass the arcuate port 56, forexample, to supply fluid pressure through port 56. The fluid pressure inpressure or discharge port 56 will deform pressure member 62 of thepiston assembly 60 and urge the piston member 61 into engagement withthe port block 30 with a force corresponding to the pressure of thefluid transmitted. A similar function will take place in the area of theintake port 55 although the pressure member 62 of the intake port issubjected to the intake fluid pressure.

Misalignment within the pump structure is allowed while yet maintainingan efficient pump function since valve plate 36 is mounted on the pins40 in a manner to allow misalignment and the essential fluid sealbetween the valve plate 36 and the port block 30 is maintained due tothe fluid pressure responsive action of the seal assembly 60. Due to theuse of the piston assembly structure 60 and the pressure surfaces 59acting as pressure loading which opposes the separating force betweenthe valve plate and barrel plate of the pump the ports 70 may be madelarger thereby inducing increased pump r.p.n1. and delivery rating. Instandard type constructions as the ports 70 are made larger theseparating force developed will increase. Thus the function of thepressure balance areas including surface 59 is to compensate for thelarger separating force when the port 70 is enlarged.

The pressure buttons 48, which have been illustrated as two in number inFIGURES 3 and 7 although additional ones may be used, are provided inthe valve plate in the areas between the intake and outlet ports 55 and56. These buttons (or pistons) as well as the surfaces 59 serve apressure balancing function in that fluid pressure in the cylinder portsis conducted through the bores 43 and urges the buttons 48 against theport block 30. Fluid pressure acts on the area defined by thecircumference of the pressure buttons 48 minus the area of the bores 43to urge the valve plate against the barrel plate and help to overcomethe separating force between valve plate 36 and barrel plate 35 in theareas between the ports 55 and 56 of the valve plate 36. The size ofO-rings 49 is such that when the pump is assembled pressure is appliedagainst the buttons 48 to provide a preloading function and provide asealing force prior to the pump attaining a predetermined minimumpressure output.

The structure of FIGURES 7 and 8 shows a modified form of the presentinvention in which the pressure buttons 48 are mounted within the portblock 30 and urged into engagement with the valve plate 36 by fluidpressure. Pressure is supplied from the pump outlet to bores in the portblock 30 to act on the pressure buttons 48. Thus a pressure loadingfunction is provided by the buttons 48 to help overcome the separatingforce between the valve plate and the barrel plate.

In the structure of FIGURE 1 the pressure buttons 48 receive the exactfluid pressure within the cylinder 13 which is opposite the pressurebuttons at any given time, thus the pressure buttons 48 in FIGURE Iserve a pressure balancing function. In the structure of FIGURE 7identical pump pressure is imposed on each of the pres sure buttons,thus providing a pressure loading function as distinguished from thepressure balancing function of FIGURE 1. The structure of FIGURE 7 mayalso be constructed having a predetermined fixed pressure imposed on thebuttons 48 as for example supplied by a charge pump or other source.

It will also be apparent that the piston assembly 60 can be mounted inport block 30 (although not illustrated) rather than in the valve plateas shown in FIG- URE 1. The operation of the piston assembly would bethe same if mounted in port block 30.

As will be apparent from the above description the present inventionprovides a fluid pump or motor of increased capacity since the ports tothe pump cylinders have an increased area. The increased area ispermitted due to the use of pressure responsive areas which serve toprovide a sealing force in accordance with the fluid pressure existingin the pump ports to thereby compensate for the separating force betweenthe valve plate and the barrel plate elements of the pump.

Due to the use of the floating valve plate construction of the presentinvention the cylinder barrel 12 may be fixedly mounted on the driveshaft 11 and misalignment problems are compensated for by the floatingvalve plate. In known constructions often the cylinder barrel is mountedin a manner to provide for slight displacement or movement of thecylinder barrel to compensate for drive shaft deflection. The commonproblem found in the prior art devices using what may be termed afloating cylinder barrel to provide for misalignment is that the heavymass of the cylinder barrel when flexibly mounted is hard to control andunder certain types of vibrations may deflect the shaft on which it ismounted creating an unbalance condition, or, in the case of a suddenstrong vibration, may move to the extent to lose its seal with thebarrel plate and valve plate completely.

Further, due to the use of the floating valve plate construction and thepressure responsive areas to overcome the separating force between thevalve plate, barrel plate and the cylinder block, construction of thecylinder block has been made possible utilizing cylinder bores for thepistons which extend through the cylinder block rather than havingcylinder bores partially closed on one end as in known constructions.Thus, manufacture of the cylinder block is simplified by eliminating thenecessity of machining of the cylinder bores to a controlled depth.

Various of the features of the invention have been particularly shownand described; however, it should be obvious to one skilled in the artthat various modifications may be made therein without departing fromthe scope of the invention.

We claim:

1. In a fluid pump or motor, a cylinder barrel having a plurality ofcylinders therein with a piston reciprocal in each cylinder, a portblock adjacent said barrel, a valve plate between said port block andsaid barrel, said valve plate being mounted for relative movement withrespect to said port block, said cylinder barrel having relativerotation with respect to said valve plate and port block, said valveplate including a fluid intake and pressure port, a piston assemblymounted in a recess in said valve plate and surrounding at least oneport, said piston assembly including a piston member in contact withsaid port block to provide a fluid seal for said port, resilient meansin said piston assembly urging said piston member into engagement withsaid port block, said resilient means being responsive to fluid pressurein said port to urge said piston member into engagement with said portblock with additional force whereby said fluid seal will be maintainedunder conditions of misalignment between said valve plate and said portblock, said recess including a pressure responsive surface surroundingsaid port, and said surface acting to overcome the separating forcebetween the cylinder barrel and said valve plate when said fluid pump ormotor is in operation.

2. A fluid pump or motor as claimed in claim 1 wherein said pistonassembly further includes a retainer to retain a resilient means withinthe piston assembly.

3. A mechanism as claimed in claim 1 wherein said cylinder barrel isrigidly mounted on said shaft for rotation therewith.

4. A mechanism as claimed in claim 1 including a plurality of pressurebuttons mounted in said valve plate arcuately disposed between saidintake and discharge ports and adapted to receive fluid pressure fromsaid cylinder and exert a balancing force in response thereto upon saidvalve plate.

5. A mechanism as claimed in claim 4 including resilient means mountedin said valve plate and urging said buttons outwardly of said valveplate to provide a preloading function.

*6. A fluid pump or motor as claimed in claim 1 includ ing a barrelplate mounted between said valve plate and said cylinder barrel and inengagement with each.

7. A fluid pump or motor as claimed in claim 1 wherein said pistonmember is made of a relatively non-resilient material and said pistonassembly further includes a resilient member in engagement with saidpiston member.

8. A fluid pump or motor as claimed in claim 7 wherein said intake andpressure ports, piston member and resilient member have an arcuatekidney shape.

9. In a fluid pump or motor, a cylinder barrel having a plurality ofcylinders therein with a piston reciprocal in each cylinder, a portblock adjacent said barrel, a valve plate between said port block andsaid barrel, said cylinder barrel having relative rotation with respectto said valve plate and port block, said valve plate including a fluidintake and pressure port, a piston assembly surrounding each port andmounted in said valve plate, said piston assembly including a pistonmember in contact with said block to provide a fluid seal for saidintake and pressure ports, resilient means in said piston assemblyurging said piston member into engagement with said valve plate, saidresilient means being responsive to fluid pressure to urge said pistonmember into engagement with additional force whereby said fluid sealwill be maintained under conditions of misalignment between said valveplate and said cylinder barrel and including a plurality of pressurebuttons mounted in said port block arcuately disposed between saidintake and discharge ports of said valve plate adapted to have fluidpressure imposed thereon and exert a balancing force in response theretoupon said valve plate.

10. A mechanism as claimed in claim 9 including resilient means mountedin said port block and urging said buttons outwardly of said port blockto provide a preloading function.

11. A mechanism as claimed in claim 9 wherein pump output pressure isimposed on said pressure buttons.

12. A mechanism as claimed in claim 9 wherein a fixed fluid pressure isimposed on said pressure buttons.

13. In a fluid pump or motor, a cylinder barrel having a plurality ofcylinders therein with a piston reciprocal in each cylinder, a portblock member adjacent said barrel, a valve plate member between saidport block member and said barrel, said valve plate mounted for relativemovement with respect to said port block, said cylinder barrel havingrelative rotation with respect to said valve plate member and said portblock member, said valve plate member including a fluid intake andpressure port, a piston assembly surrounding each port and mounted inone of said members, said piston assembly including a piston member incontact with the other of said members to provide a fluid seal for saidintake and pressure ports, resilient means in said piston assemblyurging said piston member into engagement with said other member, andsaid resilient means being responsive to fluid pressure to urge saidpiston into engagement with additional force whereby said fluid sealwill be maintained under conditions of misalignment between said valveplate member and said port block member.

7 8 14. A fluid pump or motor as claimed in claim 13 3,051,093 8/1962Budzich 103-162 wherein said piston assembly is mounted in a counterbore3,175,510 3/ 1965 DAmato 103l62 in one of said members, said recessincluding a pressure 3,183,846 5/1965 Skinner 103162 responsive surfacesurrounding said intake and pressure 3,191,543 6/1965 Hann et al. 103162ports, and said surface acting to overcome the separating force betweenthe cylinder barrel and said valve plate FOREIGN PATENTS member whensaid fluid pump or motor is in operation. 234,963 10/1960 Australia-References Cit d WILLIAM L. FREEH, Primary Examiner UNITED STATESPATENTS 10 I US. Cl. X R. 6,75 7/1953 Overbeke 103 -161 103161 2,845,9418/1958 Wagner 103162 X

